A swatch of Altocumulus perlucidus translucidus (sorry, that’s the way we talk around here) passed over Catalina early yesterday afternoon, each “unit” nearly perfectly evenly spaced with its fellow cloud element creating a brief period of cloud awe for those Catalinans (or is it, “Catalina-ites”? “Catalinians”? Who knows, who cares?). Here it is, in case you work indoors and missed it. It was truly a fabulous sighting!

1:16 PM.1:16 PM. Starting to take too many pictures of the same thing!1:16 PM.1:16 PM, of course. So pretty.

The afternoon was marked by a melange1 of middle clouds:

1:52 PM. Altocumulus opacus with a Cirrostratus above.3:11 PM. Some equestrians on horses (haha) went by the house. Sometimes we focus too much on just clouds here, and so we offer the reader who visits here an occasional relief from cloud fatigue.3:12 PM. Those equestrians were being shaded by a Altcumulus perlucidus and by an overcast of Cirrostratus. If you look real hard, you can see a faint halo. The Cirrostratus was thickening upwind as an upper level wave approached and was increasing the amount of rising air aloft over us. The Altocumulus clouds also thickened toward sunset. See below.5:07 PM. Heavy Altocumulus approached from the SW, keeping the sun from under-lighting the Altocumulus as it went down, so no flaming sunset last night. The Cirrostratus overcast continues. All in all, a fine day for Catalinians!

The weather just ahead

The local TEEVEE met men are, of course, pounding out the good news rain is just ahead for Catalina. Looks like, oh, 100% chance to CMP (Cloud Maven Person) starting after midnight Tuesday to Wednesday. How much?

This is a potent, but fast moving trough. Maybe will have only 2-4 h of rain with the passage of the cold front and its rainband. But, coming from the sub-tropics, should have a appreciable rain band with it.

I would expect rainrates to reach “moderate” as the heart of the band goes by for a coupla hours, anyway. Moderate rain is defined by the NWS as 0.1 to 0.3 inches per hour. So, only two hours of moderate rain should be at LEAST 0.2 inches, and most likely more.

We’re thinking here that there’s a 90% chance of more than 0.15 inches, and a 90% chance of less than 0.70 inches. So, averaging those two leads to a best estimate in CMP’s opinion of 0.425 inches! Wow. Nice.

Now, I will look at the U of AZ nested model and see what it thinks. Kind of game we play here, seeing how a seat of the pants forecast, made over a coupla minutes, measures up to a computer model with billions if not trillions of calculations:

Cumulative rainfall ending at 3 PM AST Wednesday afternoon. Catalina is in the GREEN, indicating that the Beowulf Supercluster thinks we’ll have over half an inch (Ms Mt. Lemmon, over an inch!) I am so happy!

The weather way ahead

After the nice rain just ahead, we have to get through the week-long dry spell before we move into a new stormy regime. First, a spaghetti depiction of the ridge after our nice storm:

Valid at 5 PM on the 14th. Huge ridge has stacked up along the West Coast, making it look like the drought will continue ad nauseum. You’ll be discouraged when the middle of January comes around (though by then, everyone will know this is a straw ridge, will collapse in almost hours from this time from the outputs made in real time then.)

Here’s what’s been exciting for a few days now, and below, from last evening’s global model output:

Let’s see what the actual and very latest model run from IPS Meteostar has for us:

From the 11 PM AST last evening global model output this big boy. Unlike so many prior troughs that were bogus this winter at this time ahead (two weeks), this one has spaghetti support and will be real!!! And, it won’t be the only one!!! I’m shouting again!!!

How much these coming rains can benefit our spring wildflower bloom and spring grasses I don’t know, but I sure hope they can resuscitate what otherwise will be a dismal spring.

Expecting a snow event during the “new regime” that takes over after mid-month, too. Be ready!

First, I will shamelessly plug a book on clouds, “A Sideways Look at Clouds”, by a well-published and acclaimed author friend, Maria Mudd Ruth. Its about her odyssey into them, mentally and physically, after she realized they were something she really had not paid much attention to before mid-life, then she had to know EVERYTHING about them! Its a great read, infused here and there with humorous anecdotes.

6:43 PM yesterday. If you look hard you can see there wasn’t much of a rain shaft with these guys. Bases were too high, updrafts pretty weak, so not a lot of water “topside” to come out.

Not that there have been that many rainstorms since the end of July.

But it would seem that today marks the meteorological end of the summer rain season as dry westerly winds sweep our remaining tropical air to the east today. The mods think there is a chance for a couple of high-based thunderstorms in the area around Catalina late in the day. But bases will be so high that not a lot of rain will reach the ground even if one passes right over us. And, they’ll be moving in from the SW or W today due to encroaching westerlies.

In a little over a week, too, you’ll be hearing about early snow in the Rockies and West! We’ll have a day or two of those gusty, dry southwest winds that accompany our winter storms as well. You’ll get a real feel for the season change then.

Check out this plot from the NOAA spaghetti factory showing (blue lines) that an unusually strong upper trough will absolutely dominate the West in just over a week

Valid on Thursday, September 21st at 5 PM AST. As this develops it draws a tropical storm northeastward out of the Mexican Pacific into New Mexico. Lucky for them!1:48 PM, September 11. Nice to see those blue skies again after so many smoky days! Here Cumulus humilis, Cumulus fractus (shred clouds) dot the sky.4:56 PM, September 11. The remaining smoke is still enough to produce crepuscular rays below Stratocumulus and Cumulus (blob on the right).6:30 PM. Orangey sunset speaks to remaining smoke. The clouds are a Stratocumulus with Cu underneath on the right.4:46 PM yesterday. The drama of lighting and shadows is about the only drama we might see now for a LONG time! Still these kinds of scenes are so wonderful; never get tired of them, which is strange.4:57 PM. Even yesterday, amid all the blue, you could still see a lofted layer of haze, typically thickest near cloud base and within cloud layers where the relative humidity is highest and some of the haze particles have “deliquesced”, adsorbed water, fatten up and scatter the light more effectively helping to produce that hazy look in toward the sun (called, “forward scattering.”) Can you see the slender icy top protruding down there in Mexico. We’ll go zooming next so you can see it. Good for you if you entered it in your cloud diary!4:57 PM. Zoomed view of that little protrusion of ice. Only a few drops would come out something like that as it developed. Here its pretty much in its dead phase, likely no base under this ice cloud. The horse icon wind vane is that of a trotter racing horse. Mom was a horse trainer and this is hers! In case you don’t believe me again, see below:Mom in 1957 or so. She passed a year ago in July.4:58 PM yesterday. More shadow drama. Expect more of this later today.

3:55 PM. Rainbow fragment and solar home, an extraordinary combination.. It was yesterday’s visual highlight. Yours for $1995.95. And, if you order now, we’ll throw in a second, exact copy of this extraordinary, magical scene FREE!

Here’s a nice one from the day before as the clouds rolled in, starting with Cirrus and Altocumulus, lowering to Stratocumulus later in the afternoon.

Yesterday’s clouds; an extraordinary day with a little drizzle amid light showers

Hope you noticed the true drizzle that occurred yesterday, namely, fine (larger than 200 microns, smaller than 500 microns in diameter), close TOGETHER (critical to the definition of “drizzle”) drops that nearly float in the air. They may make the least impression, or none, when landing in a puddle.

When you see drizzle, you have the opportunity of chatting up your neighbor by educating them informally to what drizzle really is (many, maybe most, TEEVEE weatherfolk do NOT know what “drizzle” is, btw), and 2) by telling your neighbor, if he/she is still listening to you, that the droplets in the clouds overhead must be larger than 30 microns in diameter, or better yet, “larger than the Hocking-Jonas diameter of 38 microns, at which point collisions with coalescence begins to occur” and “drizzle is not produced by ice crystals in the clouds overhead; they’re not enough of them to produce ‘fine, close together drops.'” Your neighbor has likely left the building at this point, but, oh, well, you tried.

Here, in Arizona, shallow clouds, such as we had yesterday, hardly ever can produce the broad droplet spectrum in which clouds have droplets larger than 30 microns in diameter. Its because this far inland from the ocean, where the air is very clean, the air has picked up natural and anthro aerosol particles that can function as “cloud condensation nuclei” (CCN). As a result of ingesting dirt and stuff, clouds have too many droplets here as a rule for the droplets in them to grow to larger sizes. They’re all mostly less than 20-25 microns, sizes in which even if they collide, they can’t coalesce.

In “pristine” areas, if you go to one, such as on a cruise out in the oceans, droplet concentrations in clouds are much lower, and even a little water that might be condensed in a shallow cloud can produce a broad spectrum, one that extends to droplet larger than 30 microns.

So even little or shallow layer clouds can precip over the oceans, produce drizzle or light rain showers (in which the larger drops are bigger than 500 microns in diameter). Of course, here we recall that the (whom some consider “villainous”) geoengineers want to stop drizzle out over the oceans so that clouds have longer lifetimes, are darker on the bottom, and reflect more sunlight back into space.

Those guys can be lumped into the same ilk as those who want to change the color of the sky from blue to whitish or yellowish by adding gigantic amounts of tiny particles in the stratosphere, again for the purpose of cooling the planet! Unbelievable. Please ask before doing this!!!

A Pinatubo sampler for what “geoengineering” would do to our skies, say, sunsets in particular. I took this photo from the University of Washington’s research aircraft in 1992 off the Washington coast in onshore flow. But we saw these same sunsets, sunrises, yellowed by the Pinatubo eruption of June 1991 everywhere we went, including in the Azores in June 1992.

OK, pretty boring, whiney, really, so inserting picture of a nice horse here to make people feel better if you’ve been depressed about what our scientists have been pondering to do about global warming other than controlling emissions:

8:57 AM. Zeus. Led cloistered life for 13 years; likes to bolt, now that he’s getting out on the trails.7:40 AM, yesterday, Dec. 31st. The low hanging Stratocumulus clouds, about 1500 feet above Catalina, and the mountains had a bit of an orange tinge. It was probably due to sunrise color on a separate much higher layer.

Later….drizzling Stratocumulus, same view:

10:30 AM. Stratocumulus praecipitatio, if you want to go “deep” into cloud naming. “Stratiformis”, too, covers a lot of the sky. Note misty-like view, lack of shafting.12:48 PM. More Stratocu P., an example of those clouds in the distance that kept dropping little and light rain showers on Catalina.1:01 PM. Highlighting amid the RW– , (weather text for “very light rain showers”). Stratcu P., with maybe Stratus fractus or Cumulus fractus below. The shadowed, dark shred clouds in the mddle would be Stratus fractus IMO.3:55 PM. Zooming in on that pretty rainbow. You know, this is a cloud heaven here. I hope you all appreciate it! Maybe that’s why I get upset over “geoengineering” and changing the sky anywhere.3:57 PM. Between showers, but new ones erupted upwind. This one have a shaft, implying a higher cloud top than the prior, non-shafting clouds that brought us semi-steady RW–.

The second extraordinary thing about yesterday was that the top temperatures of these clouds was around -10° C (14° F), temperatures that ice does not form act as a rule in Arizona. To get ice at temperatures that high, you also need larger cloud droplets, and they have to occur in the -2.5° C to -8° C range. In this range, it was discovered that falling ice crystals, mostly faster falling ones like “graupel” (aka, soft hail) when colliding with larger drops, ice splinters are produced. The cloud droplets must be larger than 23 microns in diameter in THAT particular temperature zone, something that would occur more often in our warm, summer clouds, but would rarely be expected in our winter ones.

Why?

Again, it goes back to clouds in inland regions ingesting lots of natural and anthro aerosols that cut down on droplet sizes in clouds (by raising droplet concentrations in them). Our recent rains have helped cut down on that process on ingesting dirt, for sure, and was a likely player yesterday. Furthermore, our winter clouds are moisture challenged relative to the summer ones with their tropical origins and high cloud base temperatures, a second reason not to expect larger droplets in our winter clouds.

Here is the TUS sounding with some writing on it for yesterday afternoon from IPS MeteoStar. (Satellite imagery was also indicating warmer than usual tops for precipitating clouds yesterday.):

The TUS balloon sounding (“rawinsonde” in techno speak) launched at about 3:30 PM yesterday afternoon. Balloon rises at about 1,000 feet a minute, FYI. Typically they pop up around 100,000-120,000 feet! Instrument package is parachuted down so it doesn’t conk somebody on the head. Sometimes they are found and returned to the NWS and re-used! How great is that?

Here’s the punchline: If clouds are drizzling, then they are ripe, if the tops get to lower temperatures than about -4° C for what we’ve termed “ice multiplication” or “ice enhancement”. A very few natural ice nuclei at temperatures between -4° and -10° C, say, starts the process, those forming “soft hail” which then leads to ice splinters. This is the leading theory of this anomaly of ice in clouds at temperatures only a little below freezing, if you think 23° to 14° F fits that definition.

There are exceptions where this process did not explain the ice that formed at such high temperatures, so standby for further elucidation about how in the HECK ice forms in clouds at some point in the future.

As usual, no time to proof, so good luck in comprehending what’s been written.

The weather just ahead:

The second main rainband is just about here at 9:25 AM. Cloud tops will be deeper and colder than in the prior rains, raising the possibility of some thunder today, and maybe another third of an inch of rain. Watch for an windshift line cloud (“arcus” cloud) might well be seen today. That’s always dramatic and exciting here in Catalina cloud heaven.

Oh, well. Was expecting at least 0.25 inches a few days ago, and thought maybe a heavy shower last night might pull that expectation out of the trash bucket. Monthly total now up to 0.70 inches (updated after reading NWS-style and CoCo gauges here), still significantly below average (0.96 inches). Not much else elsewhere, either. Double dang.

Mostly Cumulus humilis and flat Stratocumulus yesterday. Was looking for ice as the temperatures aloft cooled during the afternoon and evening, and only as the sun went down was a slight bit of virga visible to the west. That Stratocu deck over us was deepening upward, and began reaching the magic point where ice begins to form, probably around or a little below -10° C (14 °F) in clouds such as yesterday’s. Let’s look at a sounding from the U of AZ (as displayed by IPS MeteoStar) and see what it says about those evening clouds and see if the above is just a bunch of hooey (I haven’t seen it yet, either):

The TUS sounding launched about 3:30 PM from the University of AZ campus. Suggests the cloudy air on that side of the mountains was indeed reaching to -10° C and likely a hair lower in the slightly higher cloud tops. Our tops especially a bit later and being a little northwest of there, were surely a bit colder.

Yesterday’s clouds

9:31 AM. Nice scruff of maybe Stratocumulus lenticularis topped Ms Lemmon, and indication of the lower level moistening that took place overnight with a dry front going by, with another one on the doorstep. Gee, camera lens is dirty.2:45 PM. Not much going on, just a few Cu hum, “two riders were approaching and the (cold) wind began to howl.” Bob Dylan, in “All Along the Watchtower” by Jimmi Hendrix. Nobel Laureate Bob wrote a LOT of songs about weather!2:47 PM. The Mighty Fraidy Cat Zeus, waiting for the weather to change, the Cumulus clouds to fill in. Today’s blog is particularly boring so thought I would spice it up with a [icture of a large (16.2 hands) horse that saw a tire leaning up against a horse fence, twirled around and at a full sprint, as though being chased by a Tyrannosaurus rex, plowed into a clump of tall cat claw acacias and mesquite bushes. The first second of that bolt was really exciting and fun, the second second, not so much. CMP was knocked off in the midst of them, racking up a broken rib, and a lot of scratches that bled profusely. However, with all that blood on his long sleeved shirt as he walked the mighty Zeus back to his corral, also chalked up quite a few “man points” when passersby saw him, I am sure. Well, there was one passerby who didn’t seem to notice as he drove by and I had to scream, “I’m OK! Its nothing, really!”2:48 PM. Nice lighting. I don’t know how many hundreds of these shots I have posted here. I just never get tired of sunlight and shadows on our mountains! Clouds still not doing anything, but its only been a minute since the last report.3:11 PM. Now we’re talking! Those Cumulus clouds are beginning to expand, fill in, transitioning to a Stratocumulus broken to overcast sky, a Stratocast (nomenclature unrelated to Fender guitars), as expected as the next front and trough approached. This was exciting. But when will the ice form in them to give us the first virga and precip?3:53 PM. Looking SW over the Oro Valley. This is really looking good. In situations like this, the clouds are forming as they travel upslope toward the Catalinas, and while they’re not preciping now, its fairly common in the situation we had yesterday for them to start preciping as the tops get chillier and chillier, often with the clearing remaining in place to the SW. That’s what I thought might happen. Things were changing fast at this time.5:15 PM. Virga and light precip were occurring on the horizon NW-NE, and these heavier Stratocu began to virga a few minutes after this. The anticipation? A nice period of light to moderate rain during the early nighttime hours as this deepening and filling in continued.That didn’t really happen. The clouds began to rain lightly here, but it didn’t measure. It was a another band coming through before midnight that produced the 0.08 inches.5:24 PM. I know a lot of you like to see pictures of the sun, so I thought I would post one today. Looks pretty round, a little bigger than usual. Don’t see any sunspots (defects) on it. That’s probably good.5:30 PM. Just after sundown the virga began to emit from this layer just beyond the Tortolitas. Really thought this would lead to a generous rain with continued deepening. Guess that didn’t happen. Probably only the best virga detectors among you saw this little curtains starting to descend from this cloud deck. I’ve added arrows to where those two patches of virga are.

Still looks like a chance for some light showers before the month closes out, but will be hard to get enough to bring the total to an above average value. Dang.

Will update my reader on December’s early cold outlook as new information that agrees with my assessment comes in. Right now, that information is not available.

Many of you probably were gasping for air after having seen the WRF-GFS model outputs from last evening’s 5 PM AST global data.

A large hurricane, really more the size of its typhoonic big brothers in the western north Pacific, and one that also dwarfs the late tropical remnant, “Newton” , that came through here a week or so ago, is shown to move along the SAME path as Newton into Arizona in about 13 days from now.

For those few of you who did NOT peruse the 00 GMT, CUT, Z output, here are the fantastic fantasy hurricane depictions that this model, with all of its calculating power, shows entering AZ on the 26th. Kind of fun to see even if it is bogus because it indicates that such a strong tropical cyclone could come through here one day.

Below, from IPS MeteoStar, these, maybe the best fake AZ hurricane depictions I have ever seen. Note all the isobars, i.e., lines of equal pressure with this tropical cyclone in AZ, and then remember for all its rain, little Newton had virtually no signature on pressure maps! Hell, the pressure didn’t even fall at Nogales as Newt approached. Pitiful.

But it wouldn’t be like that in this fantasy hurricane. Tremendous pressure falls would occur as it entered AZ giving your microbarograph quite a workout as the pressure plummeted and then went up as the center passed by.

Next, you’re curious, though, about what steering pattern caused this hurricane, previously shown to stay far offshore and dissipate over some jellyfish and plastic particles way out in the Pacific in the models.

Let’s look, again from IPS MeteoStar at the steering situation at 500 millybars, or in around 20,000 feet or so:

Here the configuration. You’re breathing a sigh of relief, maybe even chuckling: “That’s not gonna happen.” Ludicroous really, though withing the slightest realm of possibility, maybe one in a thousand. Like kicking a field goal that goes through the uprights after bouncing off an opposing player’s helmut. I mean, it could happen, like a golf shot at Carmel that bounces off a stunted cypress and goes into the hole from 500 yards out, or…. OK, enough of that.

What you need to have any confidence is a big trough along or just offshore as we had with Newt, not a slight little itty bitty eddy aloft that has to be in exactly the right location at EXACTLY the right time. I mean, its like a ball that goes for a home run after it bounces of the center fielder’s head1 …

Hold your cash on the sand bags.

Finally, there’s really nothing from the spaghetti factory that supports this. Boohoo. What you need in spaghetti is strong support for a trough along the coast, not the below:

Valid at 5 PM AST September 25th.

Yesterday’s clouds

Spectacular Altocumulus castellanus and floccus (no virga) passed overhead during the morning. I hope you documented them with a few photos.

9:11 AM, on the trail looking at a superb example of Altocumulus floccus. Estimated height, 12,000 feet above ground level. No ice visible, so tops likely warmer than -10 C. The bases of these clouds evaporated almost as soon as they formed, but the tops not so much, rose steadily after bottom disappeared. Tallest ones were likely more than 1,000-2000 feet tall.12:16 PM. By this time, which was good, smallish Cumulonimbus clouds recurred over the Catalina Mountains mostly east of Ms. Lemmon. Nice stages of ice development in the tops from newly risen, no sign of ice (right side here), to frizzy all ice remains (left side here), over and over again.

Horse story

Have to depart from clouds and weather to tell this tale. Yesterday I stopped here to let the mighty Zeus rest a little. I let him graze “off leash” on some of the still-green nettle grass in a gravel parking area next to our cottage. I then went to get a pail of water for him, the pail being on the north side of our house. When he saw I was leaving, he immediately followed me like a dog. It was kind of cute.

But as we got to the gravel outside the north porch of our house, our two dogs, Banjo and Emma were going nuts at the sight of a horse outside the north windows.

Zeus got distracted by all of the commotion in the house and went onto the porch to look in one of the windows to see what was up, or maybe he saw his own reflection and thought it was another horse? Here is the hilarious scene:

2:21 PM yesterday. Zeus looks in to see why the dogs are barking so much.

The End

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1This actually happened in South Dakota, at Mitchell’s Cadwell Park, during a baseball game I played in ’72. I was catching in those days for Mitchell Commercial Bank. Our center fielder, a track star, ran to get a scorching line drive to medium depth center, and racing to his left, reaching up to grab it, the ball instead bounced off his noggin and went some 40 or 50 feet over the fence! He was OK. We had no “concussion protocol” in those days. Had a chance to bat against the legendary Canova, SD, pitcher, Lee Goldammer in that game. Whiffed on three pitches; was maybe at bat for 30 seconds.

Surfaris. Except it wasn’t funny. This song begins with a mocking laugh. Well, maybe “mocking” is correct.

Used 90 min of video on an “incoming” yesterday, thinking we’d get shafted pretty good as a thin line of heavy Cumulus congestus transitioning to Cumulonimbus passed over, maybe a quarter or more of an inch from both warm rain and ice processes1 in a line of clouds produced by the winds resulting from a strong fall of rain from a cell just north of Biosphere2. I am sure you were thinking the same thing and are profoundly disappointed today, not only by that one, but also by that Big Bopper that formed in the late afternoon around the same spot to the north-northeast of us.

10:33 AM. Icy topped cell has unloaded N of the Biosphere2 and a line of heavy Cumulus have formed above the outflowing wind boundary, creating a line of rain headed this way!10:49 AM. Outflow winds pushing nice, fat Cu up, and its getting closer raising hopes.11:16 AM. Good rain shafting moves into Saddlebrooke. I can feel the huge drops! MIght even be an all warm rain process shower, too, Wind shift almost here, though it is taking its time, I begin to think.11?39 AM. Shaft thinning by the second! Dammitall. Wind shift, rain drops still not here! This is now looking horrible. Cloud base above wind shift narrowing, falling apart, too. This could be the worst day of my life.11:58 AM. Rain, wind and wind have quit. Shaft is transparent, Code 1 maybe, easily seen through. 0.04 inches registered by Davis Vantage Pro Mark IV super-duper personal weather station.

Wished I’d copied that Wundermap of precip amounts at personal weather stations, but here they are, to reinforce the concept of a “wipeout“:

North of Saddlebrooke: 1.04 inches

Center of Saddlebrooke: 0.53 inches

South Saddlebrooke: 0.24 inches

Sutherland Heights “video station”: 0.04 inches! Ouch.

Wind blast here out of this event? Oh, maybe 12 mph.

What started out as a happy day turned sad in a hurry.

And this wasn’t the only “wipeout“! A worse one happened in the late afternoon that was far more excruciating; pain unbearable. A real explosion into gigantic Cumulonimbus occurred in a broken line, again in the area north of Saddlebrooke. It appeared one had produced a huge outflow for a time–probably was up toward the Biosphere2.

Some background. Here’s how it all started with a gargantuan line of Cumulonimbus and Cumulus congestus clouds in familiar broken line from just north of the Tortolitas to our northwest to north of Oracle to the northeast shown in the photos below, all taken at 3:43 PM. CMP wasn’t looking when this eruption of activity suddenly occurred, and seemed to happen elsewhere as well. May have been that afternoon temperatures just reached that higher point to send these big boys up there.

3:47 PM. Looking toward Tucson as this embarrassing formation arose, Cumulonimbus calvus erectus. This tall, slender cloud was incredible because it showed how great the instability was on this day. Fat clouds we know can rise up to become huge purveyors of rain, but narrow ones like this need a lot instability, lots of humidity around the growing turret so that it doesn’t evaporate, and a good updraft so that it doesn’t take to long to reach 30-35 kft level, as estimated here. So, it was real demonstration of the type of air mass we had this day.3:55 PM. Crushing rains are now dropping out of those behemoths to the N-NE. Surely a blast of wind will come shooting south toward us!

After feeding a horse on another property, I am racing back home to experience “The Blast”, and the rain in its full glory. I stopped to grab this photo, heart pounding.

4:12 PM. “Holy Criminy!” Look at this thing, and I can just now begin to see the arcus cloud forming (just to left of where dirt road disappears) on the nose of the winds coming at us! This will be incredible!4:24 PM. There she is! Arcus rolls toward Catalina pumping clouds up above it, though, you know, those clouds above the arcus don’t look as big as maybe they should. Some doubt begins to creep in.

The arcus cloud and the once proud Cumulonimbus cloud and its incredible rain shaft wiped out, the bottom of it vaporized if that’s possible by rainout, the wind push out of it unable to reach Catalina, in spite of an auspicious start. I now insert a picture of a horse, Zeus, to keep your interest up, maybe raise your spirits after such a debilitating cloud stories as are found here today. Animals, such as dogs, miniature horses and donkeys, are often used in psycho rehab units, especially for depressed persons, such as you are right now after reading this. So, I am really doing this horse insertion for my reader, whom I have depressed royally today:

Zeus, a Paint breed horse, 16.2 hands tall, eating. Has a pleasant disposition overall.6:09 PM. Some people no doubt had two or more inches fall on them from those storms north of us, and the day ended cool, humid and overcast due to multiple layers of clouds from Cu, Ac, and As from anvils, with isolated showers as shown here toward the SSW toward Tucson. It was nice to be outside, swatting gnats and such a minor nuisance.

The End (for August 3rd–falling behind more and more!)

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1As a cloud maven junior person, of course, you know what I am talkin’ about when I mention “warm rain” and “ice processes.”

Yesterday was another great humilis day for you, with quite a phase twist at the end. I am sure most of you out there saw the surprising final touch to a warm day with high-based shallow Cumulus.

11:52 AM.11:52 AM. Cumulus humilis and fractus over the Catalinas, in case you think I was hiding bigger clouds that might have been over the mountains.5:15 PM. 95 and 25, temperature and dewpoint. What is the height of the cloud bases above ground level given a 70 degree F difference? Hint: divide difference by 5 and that’s the hieight above the ground in thousands of feet. So they were way up there at about 17,000 feet above ground level!

Let’s see how close that using that old estimator technique was yesterday by examining the Tucson sounding for 5 PM AST (launched around 3:30 PM, goes up about 1,000 feet a minute). From the Wyoming Cowboys, this:

Wow! LCLP was 515 millibars, just about exactly at 17,000 feet. Also, look how darn cold bases were, almost -10 °C or 14 ° F, tops around -14 °C or just 7 °F, and yet we see no ice…yet.

6:06 PM. Which way is the wind blowing at cloud level? Ans: at you. Nice cloud street streaming off the Catalinas over Catalina. Clouds not looking so much like Cumulus humilis anymore but rather more like Altocumulus opacus. No signs of any ice…yet.6:09 PM. Hint of ice in this photo of clouds far downwind of the Catalinas (looking north over Saddlebrook and beyond. Can you find it?6:52 PM. By this time, there was ice EVERYWHERE! It was an amazing transition from cloud lurking up there with no sign of ice, to ice in almost every cloud. Have hardly ever seen such a dramatic transformation in clouds that seem to be unable to produce ice most of the day. What happened? I don’t know. But will guess. These clouds, part of a moisture slug moving around the big trough coming in, were actually being lifted in time so that minute by minute they were getting a little colder until ice concentrations suddenly onset. Ice seems to depend on droplet sizes (the larger ones freeze at higher temperatures, AND temperature, the same size drop will freeze as the temperature falls. In clouds like this, the largest droplet sizes were likely the same before and after the transition to ice, so one would guess that the temperature at which they would freeze was reached as the tops rose due to a layer being lifted, not because some tops were higher and colder. The transition was too widespread and affected small clouds as well as the larger groupings. Well, lotta handwaving here, but it was an amazing change that transpired last evening.7:07 PM. Noticeable virga is now dropping out of those clouds, ice concentrations probably up to a few to tens per liter!7:07 PM. Looking toward the Charouleau Gap. Icy looking cloud over there, too. What is going on?7:08 PM. Nice sunset, though. Ice barely visible at right.

While waiting for some rain in the days ahead, not backing off that in any way, though models generally have not had any (bad models!), will pass along a horse prank that happened.

Two days in the morning, as I went to fill “Zeus” water tank in the dawn hours, there was something dark at the bottom of it. I thought maybe some poor little animal or bird had drowned in his tank that night. I reached down, and found it was my State Park baseball cap! I had left it on the top of a panel, maybe above the water tank, wasn’t sure, so it likely blew off the panel into the water tank. But then again, I wasn’t sure that Zeus hadn’t put it in there on purpose.

But that was a crazy thought.

As a test, yesterday morning I decided to put the cap back on top of the end of a horse corral panel, but much farther away where it could not possible fall into the tank, just in case Zeus was telling me what he thought of me by dunking my cap.

9:41 AM May 4th.

Here’s what I found when I came back in the afternoon to feed Zeus:The same scene as the prior morning!

This was amazing. I approach one of the puddles on Equestrian Trail. I see that its raining HARD in the puddle. I am only 20 feet from it, but its not raining on my car! Here’s what that scene looked like:

How could this be? Of course, we’ve all seen heavy rain on the road and drove into it. But the illusion here that was so striking is that it only SEEMED to be raining in the puddle, not around it since the drop splashes were not obvious as I drove up to it.

The rest of yesterday was pretty great, too, lots of rainbows, brilliant clouds and skies, too photogenic for a neurotic-compulsive photographer. However, one of 221 photos was of a human, a neighbor, not of clouds and rain shafts.

Here are a few too many cloud photos; excess is kind of a specialty of mine:

6:25 AM.6:25 AM.

6:25 AM. Unloading.6:26 AM.

7:40 AM.11:58 AM. Cumulonimbus cloud boils upward upwind of Catalina.12:25 PM. Getting closer….12:51 PM. Lightning strikes not that close…Hail up to pea size, though.1:10 PM. Backside of storm looked pretty good, too, quite firm and protuberant, indicating updraft still intact. Note whitish fallstreak, likely graupel and or hail.1:10 PM. Horse exults over extra rain.1:43 PM. Crepuscular rays due to rain, not haze. A pretty scene sez me.2:18 PM. Another dramatic scene.2:36 PM. Biosphere 2 hit by light rainbow.2:42 PM. For the sharp-eyed, bit of arcus cloud below Cumulus bases shows the northwest wind and cold front about to hit Catalina. Hit over there by Marana first. Was minutes away here.2:46 PM. Something akin to an arcus cloud is just about on Catalina. Remember, the shift of the wind precedes the cloud, and lifts the air above it. Did you notice how the whole sky began to fill in with clouds as the windshift hit and for the hours after that? Pretty cool, huh?3:56 PM. Awful dark out for this time of day. And yet another rainbow! Is this Hawaii, or WHAT? Rainbow colors end where snow is falling, not rain.

4:05 PM. Day closes with more storms drifting toward Catalina.

Lightly looking ahead

Still a lot of “troughy” weather ahead, and chance for decent November rains in the first half of the month after cold one goes by, followed by a short dry spell.

Beginning to wonder, with all the middle cloud thickness out there over and SW of Baja that’s headed this way if we won’t get sprinkles that produce a little measurable rain later today or overnight….

7 AM AST. Look at all those clouds over Baja and to the west of there.You can see this whole loop from the Washington Huskies here.

Models beginning to wetten things up here as well, like that Enviro Can model that sees our tropical surge high and middle clouds passing over us now, as deep enough for measurable rain later today and overnight. Huh. U of AZ mod, the best one for us, is still dry around here except on mountain tops. Our larger scale model, however, also has some very light rain in this area now, later today into tomorrow morning.

What’s intriguing is that a little jet core at 500 mb (up there at about the height of middle clouds) passes south of us as this happens, key for precip here1 in the cool season. The major jet stream is far to the north.

As you know, we have a bit of an El Niño going, both a “Classic Niño” as well as the “New Niño” going, and El Niños strengthen the southern portions of jet streams in the very way that we’re seeing in this situation.

They do that because its warmer than usual in the central and far eastern Pacific tropics due to heat in extra big Cumulus and Cumulonimbus clouds that pump away down there over that extra warm water, and that rising warmth produces a greater than usual difference in temperatures throughout the troposphere between the tropics and the mid-latitudes. Since jet streams are the products of temperature differences between warm and cold air around the globe, so unusually deep warmth in the tropical eastern Pacific gives a little strength tweak to jet streams coming into the coast2.

SInce there are two of these lower latitude “waves” traveling along in the southern branch of the jet stream, there are TWO chances for slight rains including that for later today. The next one barges in on the 6th of December. Will again be dense middle and high clouds with virga at its worst, like this one, though again a hundredth or two could happen.

Next real rain chance, and major front passage with air that’s too cold for us, will be on the 12th. Spaghetti folk, or “Spaghetti Busters”, those who can make sense of these balls of yarn, can EASILY see that trough on the 12th and a cold front with are “in the bag” even though that’s ten days away. Rain occurrence is more dubious, since the trough may land a bit too far east to produce rain, only a lowering of temperatures. Here is that plot from last evening. Enjoy.

Valid at 5 PM, December 12th. Pretty clear a nice trough will be in the area then.

Your yesterday’s clouds

11:44 AM. Up and down, up and down, those wavy air motions that produced this interesting line.3:37 PM. Classic Altostratus translucidus (sun’s position is visible).5:20 PM. Sunset Altostratus (ice clouds) and Altocumulus (droplet clouds).

BTW, for horsey people, the Cement Trough had water in it yesterday after being completely dry ten days ago:

11:44 AM. At the Cement Trough headed to South Gate.

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1See Rangno, 1973, unpublished manuscript and figures for the whole US using only the horizontal shear in jet stream at 500 mb as a definer of precip occurrences. Its really quite something, though, I guess you can’t see it.

2This was figured out by the Great Jacob Bjerknes of the Norwegian School of Meteorology while he was cruising into retirement (“Emeritus” status) at UCLA in the 1960s, though Chuck Pyke3,4, his grad student, did most of the work. Did a lotta work on the big “Classic” El Niño of 1957-58, which, per chance turned out to be an International Geophysical Year with a lot of extra observations! How lucky wazzat?

3Chuck, as you may recall was in the National Guard whilst at UCLA and was sent to Biloxi, MS, for two weeks of training and while there, was “gifted” with the passage of the eye of Hurricane Camille, one of the strongest of the century. Later the remnants of Camille, to go on and on, produced 31 inches of rain in 6 h in Virginia.

4Chuck P, who now lives in Arizona, also was very thorough in his evaluations of rainfall in his other studies concerning the seasonal timing of rainfall throughout the West. He once told me when I visited UCLA once to get Bjerknes autograph5 that he had gone to every rainfall measuring site in his study! Now some people go to every baseball park in America, but going every rain gauge site would be more interesting to cloud mavens. He further told me he found one that had not moved for 30 years, but the rainfall had been decreasing. When he went to that gauge, he found that it was being overgrown by a tree! This is why you have to check things.

5I failed. He was “Emeritus”; too good to be in his office that day. You see, your Catalina cloud maven was a strange person even then, wanting an autobgraph by Bjerknes rather than one by Mickey Mantle, though one by Mickey M would be worth a lot more today.

While living the big western life yesterday by riding a horse, me and my ridin’ pal, Nora B., came across some water flowing in the Sutherland Wash by the rusty gate on the east side of the wash that leads to Coronado National Forest land.

So, with with a 3-5 inch rain on the Catalinas, there WAS some water in the Sutherland here in the Catalina area. It was remarkable that there was no sign whatsoever of water having flowed at the Cottonwoods at the Baby Jesus Trail head on the north side of this flow (shown below), but water was flowing in it a few hundred yards farther downstream.

Nor was there any sign that water had flowed from our big rain in the Sutherland Wash at the back gate to Catalina State Park. In fact, we saw where this Sutherland Wash water disappeared just down from the rusty gate.

So, a lesson has been learned here about wash water flows: it can be flowing modestly between two dry points. Huh. Might not see this again for some time, and it will all be going away soon. Too bad so many of us have to pass hiking or horseback riding to these rare scenes today due to a necessary Pac 12 football TEEVEE vigil beginning just after 12 noon today and lasting through midnight I think. Kind of sad when you have to make choices between two equally worthy activities like these.

Cloudwise, I hope you logged the occurrence of distant Cumulonimbus clouds in the high country on the NW-NE horizon late yesterday afternoon.

The End.

9:18 AM. The Sutherland Wash near the rusty gate.9:54 AM. The apparent source of the water, the tributary Big Rock creek a few hundred yards south of the Baby Jesus trail head at the Cottonwoods.